The present invention relates to a self-propelling machine for processing bituminous or concrete pavement material. The self-propelling machine may be a road finisher.
Road finishers are known e.g. from the following publications: DE 20 2007 003 326 U1, DE 20 2004 016 489 U1, DE 10 2004 002 658 A1, DE 299 23 118 U1, DE 299 20 556 U1, DE 299 15 875 U1, DE 296 12 035 U1, DE 296 12 034 U1 or DE 196 34 503 B4. Such road finishers can be driven by a wheel-type running gear, as described in DE 299 20 556 U1, or by a tracked running gear, as described in DE 299 23 118 U1. They are normally provided with a material bunker for accommodating the pavement mix which will form the road surface. With the aid of conveying means, e.g. scraper belts, the pavement mix is conveyed from the material bunker to the area of the road finisher located at the rear when seen in the direction of travel. In this rear area, the pavement mix supplied is distributed across the whole laying width, normally by means of a lateral distributor, e.g. an auger. Finally, the road finisher also carries a so-called screed, which is arranged behind the lateral distributor when seen in the direction of travel. It is used for smoothing and compacting the paving material applied, and, to this end, it may be provided with tampers, vibrating screed plates and/or pressure bars, by way of example.
Road finishers are driven by means of an engine, which is normally an internal combustion engine. In most cases, diesel engines are used. In addition to the driving power, the engine also provides power for operating a generator by means of which current is generated for operating a large number of components of the finisher. The current can, for example, be used for operating the lighting, the control, pumps for hydraulic components and, in particular, electric heating units. Such heating units are normally provided at all the components which come into contact with the pavement mix so as to prevent the latter from cooling down and solidifying on the components of the road finisher. Electric heating elements are especially provided on the screed, since this is the location of the road finisher where the strongest decrease in the temperature of the pavement mix has already occurred.
Due to its weight and the large number of driven components, and also due to the necessity of operating the heating elements, the amount of fuel consumed by a road finisher is comparatively large. In view of the rising energy prices, there is a significant rise in the contribution of the energy costs to the total operational costs of a road finisher. A 10 to 20% reduction of the amount of fuel consumed would already save, per year, several thousand liters of the fuel required for operating a road finisher. This would not only be beneficial to the environment but it would also reduce the operational costs of a road finisher to a significant extent.